Khan Academy
Hubble's Law
Sal defines and explains the premise of Hubble's Law and then uses trigonometry to show the relationship between velocity and distance. He explains that as the universe expands, objects get farther away from each other; as objects move...
Krista King Math
Nets of Cones
Use a net to catch your classes in the process of learning! A video instruction demonstrates how to draw the net of a three-dimensional cone. The nets include scale and labeling of dimensions.
Curated OER
Systems of Three Variables 2
Sal uses the elimination method to simplify a system of three variables. Next, he employs the substitution method to check his solution. This resource would nicely complement any lesson on this topic.
Curated OER
Multiplying Fractions and Mixed Numbers
Here is a great video explaining how to multiply a fraction by a whole number. Sal shows students how to put a whole number over 1 in order to multiply it by a fraction. He simplifies his answer and writes it as a mixed number.
Curated OER
Anatomy of a Muscle Cell
Previous videos have dealt with the proteins that produce mechanical motion and how nerves stimulate contraction. But this presentation explains on a gross anatomical scale, how skeletal muscle is structured.
Curated OER
Parallax in Observing Stars
Parallax is the apparent change of an object determined by the line of sight. Sal defines the concept of parallax and applies it to how we determine the relative distance between us and near-by stars. He draws a diagram to illustrate...
MinutePhysics
This is Not a Rainbow
A color-based video explains how scientists identified the colors of the rainbow and why we see different colors at different times. It introduces the idea of supernumerary colors and the disc shape of a rainbow as well.
Curated OER
Red Shift
The Red Shift concept can be one of the most confusing in physics. Learners may find it helpful to start with learning more about the Doppler Effect before introducing this video.
PBS
When Fish Wore Armor
Today very few animals exist with both an endoskeleton and exoskeleton. Yet, in the Devonian period, a large number of fish species lived with both. Scientists debate if they were for protection or mineral storage, because none of them...
Curated OER
Structure of the Earth
Salman Khan goes into detail about the layers of the Earth. He provides names and general numbers about depths and composition.